With Audio Hijack Pro, you can create enhanced podcasts, with audio from many sources, record streaming radio, record audio chats, save audio from records (LPs), cassette tapes, and other analog sources.

This is a really useful app, great for grabbing bits of streaming audio, or scheduling live broadcasts. The Pro version allows you to set lots of stuff and do some processing with its support for plug-ins. The Skype capture with one channel for the sender and the other for the receiver is very useful.